FIELD OF THE INVENTION
This invention relates to novel compositions classified in the art of chemistry as organic peroxides, more specifically to organic peroxide blends which are liquid at room temperature, their method of preparation and their use in curing peroxide crosslinkable polymers.
Still more specifically the organic peroxides comprise alpha-alpha'-ditertiary alkylperoxy derivatives of the meta, or mixed meta, para isomers of diisopropylbenzene. The compositions are useful in curing peroxide cross-linkable polymers and in initiating polymerization reactions of suitable monomers.
The novel compositions of the invention include a peroxide blend which comprises 5 to 65 parts by weight of bis(2-t-butylperoxy-2-propyl)benzene, a diperoxide of Formula I ##STR1## from 10 to 55 parts by weight of 1-(2-t-butylperoxy-2-propyl)-3 or 4-(2-t-amylperoxy-2-propyl)benzene, a diperoxide of Formula II ##STR2## and from 3 to 55 parts by weight of bis(2-t-amylperoxy-2-propyl)benzene, a diperoxide of Formula III ##STR3##
Wherein the meta to para isomer ratios of each of I, II and III are selected to provide a blend which is liquid at 25.degree. C. or lower.
Preferably, the peroxide blend comprises from about 7 to 61 parts by weight I, from 30 to 55 parts by weight II and from 3 to 47 parts by weight III where the ratio of the meta isomers to the para isomers can vary from at least 1.5:1 to all meta isomers.
More preferably, the peroxide blend comprises from 35 to 60 parts by weight I, from 35 to 55 parts by weight II, from 5 to 20 parts by weight III and the ratio of the meta isomers to the para isomers can vary from at least 1.5:1 to all meta isomers.
The peroxide blend may optionally contain small amounts, up to 15% by weight of the peroxide blend, of the meta, para or a mixture of the meta and para isomers of the monoperoxides of Formula IV ##STR4## where R may be t-butyl or t-amyl and R' may be hydrogen, isopropyl, isopropenyl or 2-hydroxy-2-propyl.
The novel blends are efficient crosslinking agents for peroxide crosslinkable polymers such as low, linear low and high density polyethylene, curing agents for ethylene-propylene elastomers such as EPDM, curing agents for polyester resins and initiators for vinyl polymerization.